Impact of thrombelastography in paediatric intensive care

Thromboelastography and Its Use in Pediatric Trauma Patients

BACKGROUND/PURPOSE

Thromboelastography's (TEG's) use in pediatric trauma patients is not widely studied. Identifying clotting cascade defects can direct decision making regarding blood product transfusion.

METHODS

We performed a single-center retrospective review of all level 1 pediatric trauma patients. Data collected included demographics, diagnoses, Injury Severity Score, intensive care unit length of stay (ICU LOS), mortality, TEG values, and blood products received. We identified TEG values associated with mortality, ICU LOS, and need for blood product transfusion.

RESULTS

A total of 237 trauma 1 patients were identified. After exclusions, 148 patients were included for analysis. Most patients were below TEG transfusion cut points. Patients with elevated reaction time, K value, and fibrinolysis at 30 minutes had increased odds of mortality with odds ratios of 1.71 (95% confidence interval [CI], 1.22-2.40), 1.94 (95% CI, 1.23-3.05), and 1.15 (95% CI, 1.03-1.28), respectively. For ICU LOS, elevated reaction time, K value, and fibrinolysis at 30 minutes, α angle, and maximum amplitude demonstrated hazard ratios of 0.76 (95% CI, 0.65-0.88), 0.82 (95% CI, 0.64-1.0), 0.95 (95% CI, 0.88-0.99), 1.05 (95% CI, 1.02-1.08), and 1.04 (95% CI, 1.01-1.06), respectively. There was no association between TEG and blood product transfusion.

CONCLUSIONS

Coagulopathic patients based on TEG had higher mortality. All TEG values, as they moved toward transfusion-trigger cut points, were associated with increased mortality.

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

Viscoelastic testing in pediatric patients

A tailored transfusion algorithm based on viscoelastic testing in the perioperative period or in trauma patients is recommended by guidelines for bleeding management. Bleeding management strategies in neonates and children are mostly extrapolated from the adult experience, as published evidence in the youngest age group is scarce. This manuscript is intended to give a structured overview of what has been published on the use of viscoelastic testing to guide bleeding management in neonates and children. Several devices that use either the traditional viscoelastic method or resonance viscoelastography technology are on the market. Reference ranges for children have been evaluated in only some of them. As most of the hemostasis maturation processes can be observed during the first year of life, adult reference ranges for viscoelastic testing could be applied over the age of 1 year. The majority of the published trials in children are based on retrospective analyses describing the correlation between viscoelastic testing and standard laboratory testing or focusing on the prediction of bleeding. Clinically more relevant studies in pediatric patients undergoing cardiac surgery have demonstrated that the implementation of a transfusion algorithm based on viscoelastic testing has significantly reduced transfusion requirements and that this approach has enabled a rapid detection of coagulation disorders in the presence of excessive bleeding. Although further studies are urgently needed, experts have reviewed the use of a transfusion algorithm based on viscoelastic testing in children as a feasible approach, as it has been shown to improve bleeding management and rationalize blood product transfusion.

Thromboelastography Variables, Immune Markers, and Endothelial Factors Associated With Shock and NPMODS in Children With Severe Sepsis

Objective: Evaluate hemostatic dysfunction in pediatric severe sepsis by thromboelastography (TEG) and determine if TEG parameters are associated with new or progressive multiple organ dysfunction syndrome (NPMODS) or shock, defined as a lactate ≥2mmol/L. We explored the relationship between TEG variables, selective cytokines, and endothelial factors. Design: Prospective observational. Setting: Single-center, quaternary care pediatric intensive care unit. Patients: Children aged 6- months to 14- years with severe sepsis with expected PICU stay for >72 h. Interventions: None. Measurements and Main Results: Twenty-eight children were enrolled with median (IQR) age of 7.3 years (4.4-11.4), PELOD score (study day-1) of 11(1.25-13), and PICU length of stay of 10 days (5-28). TEG-defined hypercoagulable state occurred most commonly in 73% (94/129) of samples, followed by hypocoagulable state in 7.8% (10/129) and mixed coagulation state in 1.5% (2/129) of samples in the study cohort. In contrast, hypocoagulable state occurred most commonly in 66% (98/148) of samples based on standard coagulation parameters. In the seven children who developed shock with NPMODS compared to eight patients with shock without NPMODS and 12 patients with severe sepsis only, we found more profound coagulopathy [thrombocytopenia (p = 0.04), elevated INR (p = 0.038), low fibrinogen level (p = 0.049), and low TEG-G value (p = 0.01)] and higher peak of interleukin-6 (p = 0.0014) and IL-10 (p = 0.007). Peak lactate in the first 5 study days had moderate correlation with standard coagulation assays, TEG parameters, and selective cytokines. Peak lactate did not correlate with markers of endothelial activation. Lowest TEG -G value had moderate correlation with peak IL-10 (ρ -0.442, p =0.019), peak VCAM (ρ - 0.495, p = 0.007), and peak lactate (ρ -0.542, p = 0.004) in the first 5 study days. A combination of TEG-G value and IL-6 concentration best discriminated children with shock and NPMODS [AUC 0.979 (95%CI 0.929-1.00), p < 0.001]. Conclusion: This exploratory analysis of hemostasis dysfunction on TEG in pediatric severe sepsis suggests that while hypercoagulability is more common, a hypocoagulable state is associated with shock and NPMODS. In addition, TEG abnormalities are also associated with immune and endothelial factors. A larger cohort study is needed to validate these findings.

Thromboelastography-Guided Therapy of Hemorrhagic Complications after Craniopharyngioma Resection: Case-Based Update

PURPOSE

Thromboelastography (TEG) is a point-of-care test that evaluates the entire hemostatic process. The use of TEG is expanding in multiple pediatric surgical disciplines. However, there is very little literature regarding its application in pediatric neurosurgical patients.

METHODS

The authors provide a case-based update and literature review regarding potential applications of TEG to pediatric neurosurgical patients.

RESULTS

The authors describe a 12-year-old female who experienced a number of complications after a craniopharyngioma resection. The patient suffered multiple new intraventricular hemorrhages with removal of external ventricular drains. Standard coagulopathy tests did not reveal any abnormalities. However, an abnormal TEG value suggested primary hyperfibrinolysis, which led to a change in medical management. The patient did not suffer any further bleeding episodes after the change in treatment.

CONCLUSIONS

The authors discuss a case where TEG influenced patient management and identified a problem despite normal values of standard laboratory tests. Neurosurgeons should be aware of the potential benefits for TEG testing in pediatric patients.